Although fuel cells show promise as future energy delivery devices, they are limited in their ability to be commercialized due to several reasons. Such reasons include the cost of the catalyst, cost of the balance of plant (e.g., saturators, flow controllers, etc.) and the limited durability of the fuel cell ion exchange membrane (hereafter referred to as the “membrane”).
Membrane durability is limited by the development of membrane defects during testing and device operation. Examples of membrane defects include, 1) pinholes, where a small hole can develop in the membrane which can allow bulk hydrogen gas (H2) to flow easily from the anode to the cathode, 2) crack formation where a crack develops through the membrane again permitting H2 to flow to the cathode, and 3) membrane thinning, where diffusion of H2 from the anode to the cathode is increased due to a reduction in thickness of the membrane material.
For each case, the unintended presence of H2 at the cathode reduces fuel cell performance significantly, and may even lead to hazardous situations. Increasing the durability of the membrane will make the fuel cells more commercially feasible since they would last longer in the field. However, identifying the factors that affect those failures remains difficult. The ability to locate the specific points of failures in membrane has had limited progress, as typical diagnostic techniques are only able to determine bulk hydrogen crossover. Identifying the location(s) of membrane failures would assist greatly in developing more durable fuel cell membranes.
One known method for identifying the location of membrane failures involves infrared imaging. At membrane defect locations, the respective reactant fluids (H2 and O2) are both present and will exothermically react in the presence of a catalyst generating heat, which is then detected using an infrared thermal detector, thermal imaging device, or a layer of thermally sensitive film positioned in proximity with the membrane.
The infrared method has some significant limitations. These limitations include a requirement that a platinum electrode (or other catalyst) be present over the ion exchange membrane during testing to produce heat. There are also safety concerns because the top of the membrane electrode assembly (MEA) is exposed to the ambient conditions allowing the potential for H2 to enter the ambient environment. Moreover, the localized generation of heat may cause further damage to the membrane.